linux-kernel - [PATCH 3.19 124/175] USB: add flag for HCDs that cant receive wakeup requests (isp1760-hcd)

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Date:	Tue,  3 Mar 2015 22:15:02 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Alan Stern <stern@...land.harvard.edu>,
	Nicolas Pitre <nico@...aro.org>,
	Greg Kroah-Hartman <greg@...ah.com>
Subject: [PATCH 3.19 124/175] USB: add flag for HCDs that cant receive wakeup requests (isp1760-hcd)

3.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alan Stern <stern@...land.harvard.edu>

commit 074f9dd55f9cab1b82690ed7e44bcf38b9616ce0 upstream.

Currently the USB stack assumes that all host controller drivers are
capable of receiving wakeup requests from downstream devices.
However, this isn't true for the isp1760-hcd driver, which means that
it isn't safe to do a runtime suspend of any device attached to a
root-hub port if the device requires wakeup.

This patch adds a "cant_recv_wakeups" flag to the usb_hcd structure
and sets the flag in isp1760-hcd.  The core is modified to prevent a
direct child of the root hub from being put into runtime suspend with
wakeup enabled if the flag is set.

Signed-off-by: Alan Stern <stern@...land.harvard.edu>
Tested-by: Nicolas Pitre <nico@...aro.org>
Signed-off-by: Greg Kroah-Hartman <greg@...ah.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/usb/core/driver.c      |   12 ++++++++++++
 drivers/usb/host/isp1760-hcd.c |    3 +++
 include/linux/usb/hcd.h        |    2 ++
 3 files changed, 17 insertions(+)

--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1780,6 +1780,18 @@ static int autosuspend_check(struct usb_
 		dev_dbg(&udev->dev, "remote wakeup needed for autosuspend\n");
 		return -EOPNOTSUPP;
 	}
+
+	/*
+	 * If the device is a direct child of the root hub and the HCD
+	 * doesn't handle wakeup requests, don't allow autosuspend when
+	 * wakeup is needed.
+	 */
+	if (w && udev->parent == udev->bus->root_hub &&
+			bus_to_hcd(udev->bus)->cant_recv_wakeups) {
+		dev_dbg(&udev->dev, "HCD doesn't handle wakeup requests\n");
+		return -EOPNOTSUPP;
+	}
+
 	udev->do_remote_wakeup = w;
 	return 0;
 }
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -2247,6 +2247,9 @@ struct usb_hcd *isp1760_register(phys_ad
 	hcd->rsrc_start = res_start;
 	hcd->rsrc_len = res_len;
 
+	/* This driver doesn't support wakeup requests */
+	hcd->cant_recv_wakeups = 1;
+
 	ret = usb_add_hcd(hcd, irq, irqflags);
 	if (ret)
 		goto err_unmap;
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -146,6 +146,8 @@ struct usb_hcd {
 	unsigned		amd_resume_bug:1; /* AMD remote wakeup quirk */
 	unsigned		can_do_streams:1; /* HC supports streams */
 	unsigned		tpl_support:1; /* OTG & EH TPL support */
+	unsigned		cant_recv_wakeups:1;
+			/* wakeup requests from downstream aren't received */
 
 	unsigned int		irq;		/* irq allocated */
 	void __iomem		*regs;		/* device memory/io */


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